Design on the new medical titanium alloy Tznt for implant

Though titanium alloy is one of the bone substitutes with the widest application prospect in clinic, there are only a few titanium alloys are listed in biomedical alloy standard. Ti6Al4V, used as biomedical alloy most, is replanted from aerospace application. As a kind of biomedical materials, Ti6Al4V has some disadvantages such as having poisonous element, poor general mechanical properties and processing properties, etc. Biomedical Ti alloys Ti5Al2.5Fe and Ti6Al7Nb were studied at the end of 1990s. Compared with biomedical Ti6Al4V, their properties have no obvious improvement except substituting Fe, Nb for V. In order to refresh conventional biomedical Ti alloy and provide excellent bone substitute materials for clinic, the third generation biomedical Ti alloy has been designed as following principles: 1. No poisonous element and excellent biocompatibility; 2. Good corrosion resistance property; 3. Lower tolerance strain and modulus, good biomechanical compatibility; 4. Middle strength: σ₀ 700-800 Mpa,σ_0.2 500∼600MPa; 5. Excellent fatigue properties, fracture toughness and stress corrosion behaviour; 6. Good processing properties. Near α-type Ti alloy with lower Al equivalent has been elected as major alloying types according to synthetical analysis of alloying type and effect of alloying elements on mechanical properties, corrosion resistance and biocompatibility. Zr, Ta and Nb are the main alloying elements. Their contents in weight are Zr: 10∼15%; Nb: 1∼4%; Ta: 1∼4%(wt). The new alloy is named as TZNT. Its mechanical properties, elastic modulus, corrosion, hemolysis, cytotoxicity and implant tests have been studied systemically. Experiment results show that every property of TZNT is up to design standard (Seen Table 1-4). At present, further basic study for application have been carried out.